Patent Document No. 1 (Japanese Laid-Open Patent Publication No. 2013-174044) discloses a bulldozer in which an upper surface of an engine cover slopes down to the front (see Patent Document No. 1). With this bulldozer the workability is enhanced, since the operator is able visually to check the upper portion of the blade, i.e. of the working implement.
On the other hand, from the standpoint of protection of the natural environment, a bulldozer needs to be equipped with exhaust purification (see Patent Document No. 2). Therefore, it is nowadays practiced to mount an exhaust treatment device to a bulldozer. Recently, a selective catalytic reduction (SCR) device for treating nitrogen oxides (NOx) is desirably installed as the exhaust treatment device. When a selective catalytic reduction device is installed in a bulldozer, a reducing agent tank also needs to be mounted on the bulldozer. Moreover, the capacity of the reducing agent tank is necessarily determined such that a ratio of the capacity of reducing agent tank to the capacity of a fuel tank is equal to or greater than a certain value.